The first failure was a launch of a KH-11 photoreconnaissance satellite on 28 August 1985, when the core stage suffered a propulsion system malfunction and was destroyed by Range Safety. The flight proceeded normally until core engine start at T+108 seconds. An abnormal start transient occurred and Engine 2 began experiencing thrust decay at T+112 seconds. At T+212 seconds, Engine 1 shut down, causing loss of attitude control. The onboard computer shut off Engine 2 at T+256 seconds and began a premature separation and ignition of the second stage. With the Titan now tumbling and headed back towards land, the destruct command was issued at T+272 seconds and the KH-11 crashed into the Pacific Ocean. In addition, during Stage 1's powered flight, the oxidizer tank began leaking N2O4 which was thought to have resulted in loss of lubrication to the Engine 1 turbopump and breakdown of the pinion gear. Attempts by the Navy to salvage booster debris from the ocean floor were largely unsuccessful. Investigators also complained that tracking camera coverage during the core stage burn was inadequate.

Titan 34D-7 was the first failed launch of a solid motor-equipped Titan vehicle from Vandenberg (there had been several failures from Cape Canaveral over the years) and was particularly vexing because of inadequate launch data - the Titan III's flawless West Coast launch record meant that the Air Force felt confident enough to remove several telemetry measurements from the boosters in the interest of reduced weight and complexity. There had evidently been leaks from both the fuel and oxidizer tanks and suspicion hinged on clamps that held the propellant feed lines in place. However, the clamps had not failed on any previous launches so it was not clear why they would suddenly fail now. Some members on the investigative board even proposed that the SRBs had suffered an exhaust gas leak which caused damage to the core stage. As evidence, they noted that a piece of cork insulation had broken off one SRB shortly after launch. The official cause of the failure was "Leakage of oxidizer resulting in loss of turbopump lubrication and breakdown of the pinion gear", however most of the members of the investigative team were unsatisfied with this verdict.

As a result of 34D-7, the Air Force took measures to ensure that a repeat failure would not occur. These included reinstalling some of the deleted telemetry probes on the Titan as well as improved camera coverage - the next launch would even have aircraft flying overhead to provide additional photography.

Titan 34D-9 was prepared for launch on 18 April 1986. Instead of the advanced KH-11 satellite carried on 34D-7, this booster would have the older model KH-9, in what would be the final launch of that satellite as well as the final launch of a film capsule photoreconnaissance satellite by the United States. One hundred and twenty people were gathered in the blockhouse on a clear, cloudless Friday morning, a rare situation for the normally foggy California coast. Liftoff took place at 10:45 AM Pacific Time. It only took a few seconds for disaster to strike as the Titan catastrophically exploded just above SLC-4E, showering the launch complex as well as the adjacent SLC-4W (used for Titan IIIB launches) with debris and toxic propellant.[2][3]

Investigation quickly provided an anatomy of the failure. The right solid rocket motor ruptured starting at T+6 seconds and the resulting torque on the launch vehicle caused the left SRM to break away, triggering its automatic destruct system, blowing the first stage to pieces and rupturing the second stage N2O4 tank. The upper stages were ejected and launched through the air until a manual destruct command was sent by the range safety officer at T+20 seconds. The KH-9 was also blown up by its internal self-destruct mechanism, which was designed to destroy the classified satellite in the event of a launch malfunction. Debris rained onto SLC-4E, badly damaging the launch complex in the process and starting numerous small fires, some of which burned for up to two days. Extracting launch personnel from the blockhouse proved difficult due to the area around the pad being filled with toxic fumes and burning debris. The right SRB had come down largely intact onto a concrete structure near the pad which had nobody inside it at the time of launch (the casing rupture had damaged the Inadvertent Separation Destruct System [ISDS] lanyards and prevented proper destruction of the SRB).

The disaster drew comparisons to the Challenger shuttle accident three months earlier, which was also the victim of a solid rocket motor malfunction. However, the Titan incident was found to have a rather different cause as it had not suffered an O-ring burn-through, but instead the culprit was a small air pocket between the SRM propellant and its metal motor casing. This allowed hot exhaust gases to burn through the casing and eventually rupture the SRM. The loss of two photoreconnaissance satellites in a row also badly hampered American efforts to acquire intelligence on Soviet activities.

The Air Force, prior to finding out the true cause of 34D-9's failure, was so puzzled at the loss of two Titan IIIs in a row that, it believed for a time that saboteurs had been at work on Vandenberg Air Force Base, and it had base personnel comb the nearby hills for bullet casings.

Due to the classified payload, extensive efforts were made to clean up all remains of the KH-9, whose film reels were ripped apart into hundreds of small pieces and scattered around the pad era. The satellite debris was taken away for burial in an undisclosed location in Nevada.

Investigation found that the manufacturer of the UA1206 boosters, Chemical Systems Division of United Technologies, had virtually forgotten proper quality control measures. Due to the Shuttle program, demand for expendable launch vehicles (ELVs) was greatly reduced during the 1980s and manufacturers had been cutting costs, dropping technical personnel, and preparing to phase out ELVs. However, the Challenger disaster created a renewed emphasis on ELVs and would see a considerable expansion of the upcoming Titan IV program, originally intended for just ten launches.

The exact reason for the air pocket in the #2 SRM was never satisfactorily determined. While all of the rocket segments were at least five years old (since all flight article Titan 34Ds had been manufactured and delivered by 1982 and the production line long since shut down), there had been no similar problems on other SRBs of the same age. Thanks to Titan 34D-9 (and because an SRB malfunction was a possible cause of 34D-7's failure), more stringent measures were put in place which included X-raying SRB segments on Titans to ensure proper operating condition before launch.

SLC-4E was out of commission until October 1987, after which it was the site of the remaining two Titan 34D launches without incident.